Just a simple spreadsheet in excel. More of a historical tool and help remind me when changes are due and what water parameters were.
Also helps to keep track of when I added animals, changed bulbs, etc.
Not very geeky but effective for me.
http://www.infinitysoft.net/ReefCon/
that is for for reefcon it is a pretty good program. Many I use it to keep a log of everything that I have had and dates of when I got them